U.S. Pat. No. 7,637,570 discloses a chair having a seat and a seat mechanism, the seat mechanism permitting a lateral pivoting movement of the seat, and the seat and the seat mechanism being in such a form that one side of the seat is movable independently of the other side of the seat during the lateral pivoting movement of the seat. Furthermore, both sides of the seat are pivotably supported about an axis of rotation which is orientated parallel with the axis of a user's knees.
In contrast to the concepts followed hitherto, in the case of which the entire seat and especially the entire seating face tilt to the right or to the left as a rigid element, in the chair known from U.S. Pat. No. 7,637,570 the right-hand and left-hand side of the seat are movable independently of each other. Such a chair is capable of following the user in his natural three-dimensional movements and nevertheless of offering sufficient security when the posture is straight.
In a preferred configuration of this new concept, the seat mechanism has two lateral support arms which react independently of each other and on which the seat is supported in its front and rear region by means of ball-and-socket joints.